Biology subjects

Gasser, C. S.

Publications and source records attributed to Gasser, C. S..

2 recordsLinked to original sources

bioRxiv2022

Seedless fruit in Annona squamosa L. is monogenic and conferred by INO locus deletion in multiple accessions

Understanding the genetic basis and inheritance of a trait facilitates the planning of breeding and development programs of new cultivars. In the sugar apple tree (Annona squamosa L.), the mechanism of the desirable seedless trait in the Thai seedless (Ts) and Brazilian seedless (Bs) accessions was associated with a deletion of the INNER NO OUTER (INO) locus. Genetic analysis of F1, F2 and backcross descendants of crosses of Bs to fertile wild-type varieties showed that seedlessness was recessive and monogenic. Whole genome sequencing of a third accession, Hawaiian seedless (Hs), identified a 16 kilobase deletion including INO. The finding of an identical deletion in Ts and Bs indicated a common origin among genotypes, from a single deletion event. Analysis of microsatellite markers could not preclude the possibility that all three accessions are vegetatively propagated clones. The sequence of the deletion site enabled formulation of a codominant assay for the wild-type and mutant genes that validated the INO gene deletion as the cause of seedless trait, and can be used in the selection of new seedless varieties. The study findings and obtained progenies should be useful in breeding and introgression programs of the trait into elite sugar apple lines and into other Annonas by means of interspecific crossings.

genetics↗

bioRxiv2022

The Arabidopsis INNER NO OUTER (INO) gene acts exclusively and quantitatively in regulation of ovule outer integument development

The INNER NO OUTER (INO) gene is essential for formation of the outer integument of ovules in Arabidopsis thaliana. Initially described lesions in INO were missense mutations resulting in aberrant mRNA splicing. To determine the null mutant phenotype we used CRISPR to induce frame-shift mutations and found, in confirmation of results on another recently identified frame-shift mutation (Vijayan et al., 2021), that such mutants have a phenotype identical to the most severe splicing mutant (ino-1), with effects specific to outer integument development. We show that the altered protein of an ino mRNA splicing mutant with a less severe phenotype (ino-4) does not have INO activity, and the mutant is partial because it produces a small amount of correctly spliced INO mRNA. Screening for suppressors of ino-4 in a fast-neutron mutagenized population identified a genetic duplication of the ino-4 gene leading to an increase in the amount of this mRNA. The increased expression led to a decrease in the severity of the mutant effects, indicating that the amount of INO activity quantitatively regulates outer integument growth. The results further confirm that the role of INO in Arabidopsis development is specific to the outer integument of ovules where it quantitatively affects the growth of this structure.

plant biology↗